[PATCH 4.4 078/113] mfd: cros_ec: Add cros_ec_cmd_xfer_status() helper

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>

commit 9798ac6d32c1a32d6d92d853ff507d2d39c4300c upstream.

So that callers of cros_ec_cmd_xfer() don't have to repeat boilerplate
code when checking for errors from the EC side.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
Reviewed-by: Benson Leung <bleung@xxxxxxxxxxxx>
Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
Acked-by: Lee Jones <lee.jones@xxxxxxxxxx>
Tested-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/platform/chrome/cros_ec_proto.c |   17 +++++++++++++++++
 include/linux/mfd/cros_ec.h             |   15 +++++++++++++++
 2 files changed, 32 insertions(+)

--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -380,3 +380,20 @@ int cros_ec_cmd_xfer(struct cros_ec_devi
 	return ret;
 }
 EXPORT_SYMBOL(cros_ec_cmd_xfer);
+
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
+			    struct cros_ec_command *msg)
+{
+	int ret;
+
+	ret = cros_ec_cmd_xfer(ec_dev, msg);
+	if (ret < 0) {
+		dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
+	} else if (msg->result != EC_RES_SUCCESS) {
+		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
+		return -EPROTO;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -224,6 +224,21 @@ int cros_ec_cmd_xfer(struct cros_ec_devi
 		     struct cros_ec_command *msg);
 
 /**
+ * cros_ec_cmd_xfer_status - Send a command to the ChromeOS EC
+ *
+ * This function is identical to cros_ec_cmd_xfer, except it returns success
+ * status only if both the command was transmitted successfully and the EC
+ * replied with success status. It's not necessary to check msg->result when
+ * using this function.
+ *
+ * @ec_dev: EC device
+ * @msg: Message to write
+ * @return: Num. of bytes transferred on success, <0 on failure
+ */
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
+			    struct cros_ec_command *msg);
+
+/**
  * cros_ec_remove - Remove a ChromeOS EC
  *
  * Call this to deregister a ChromeOS EC, then clean up any private data.